The sliding surfaces of higher hardness of generic plain bearings which are typically arranged in a continuous way usually demand a more complex production process, e.g. by mechanical processing steps such as milling and re-grinding. The production effort will be especially high when such bearing surfaces need to be incorporated in a large-size integral revolving unit of an underwater power plant. Moreover, it is hardly possible to repair sliding surfaces which are provided in such a way after a certain running time of the installation. It is often unavoidable to dismount the entire installation and to re-work the shaft stub of the revolving unit in its entirety or to replace the same.